Device for deblocking optical workpieces, in particular eyeglass lenses

Abstract

A device for deblocking optical workpieces, having a first moving device for rotating a workpiece, which is blocked on a blocking piece, about a workpiece rotational axis and a nozzle for dispensing a pressurized stream in a direction that is essentially transverse to the workpiece rotational axis onto a point of incidence in an edge region between the blocking piece and the workpiece. The device also has a second moving device for generating a relative movement between the nozzle and the workpiece. The second moving device has a nozzle guiding portion on which the nozzle is mounted and by which the nozzle can be positioned with respect to the blocking piece in a cam-controlled manner in order to aim the pressurized stream towards the point of incidence in a defined manner.

The invention claimed is: 
     
       1. A system including a device for deblocking an optical workpiece, particularly a spectacle lens, from a block piece for holding the workpiece, comprising:
 a block piece and workpiece assembly, 
 a first movement device for rotating the block piece and workpiece assembly about a workpiece axis of rotation via the block piece, wherein the workpiece is blocked on a defined curved blocking surface of the block piece, which also has an outer circumferential surface, 
 a nozzle with an outlet opening for delivery of a high-pressure jet of a pressure medium via the outlet opening in a direction substantially transverse to the workpiece axis of rotation onto a point of incidence in an edge region between the block piece and the workpiece, and 
 a second movement device for generating a relative movement between the nozzle and the workpiece, wherein the second movement device has a nozzle guide section on which the nozzle is mounted and by which the nozzle is positionable with respect to the block piece under mechanically positive cam control depending on one of the geometry of the outer circumferential surface of the block piece and the curvature of the blocking surface of the block piece in order to direct the high-pressure jet of pressure medium in defined manner onto the point of incidence, constructed such that during deblocking a substantially constant clear spacing is maintained between the outlet opening of the nozzle and the point of incidence and/or the high-pressure jet of pressure medium is set to be incident on the point of incidence at a predetermined incidence angle. 
 
     
     
       2. A system according to  claim 1 , characterized in that the nozzle guide section comprises a scanning arm which can be brought into operative engagement with an outer circumferential surface of the block piece in order to maintain a substantially constant clear spacing during deblocking between an outlet opening of the nozzle and the point of incidence of the high-pressure jet of the pressure medium in the edge region between the block piece and the workpiece independently of the circumferential profile of the outer circumferential surface of the block piece and the rotational angle position of the block piece about the workpiece axis of rotation. 
     
     
       3. A device according to  claim 1 , characterized in that the nozzle guide section comprises a control plate which co-operates with at least one control cam so as to set an angle of incidence at which the high-pressure jet of pressure medium is incident on the point of incidence in the edge region between block piece and workpiece during the deblocking. 
     
     
       4. A device according to  claim 1 , characterized in that the workpiece has a first optically effective surface and a second optically effective surface and prior to the deblocking is blocked by the first optically effective surface on the blocking surface of the block piece, wherein a withdrawal device with a suction head is provided, which for the deblocking can be acted on by a sub-atmospheric pressure in order to firmly suck against the second optically effective surface so that a withdrawing force can be applied to the workpiece by the withdrawing device via the suction head. 
     
     
       5. A device according to  claim 4 , characterized in that the withdrawal device comprises a manually actuable piston-cylinder arrangement, which is pneumatically connected with the suction head, for generating a sub-atmospheric pressure. 
     
     
       6. A device according to  claim 4 , characterized in that the withdrawal device comprises a second lever mechanism, by which the suction head is manually pivotable from a rest position to a suction position and vice versa, and at least one spring, which through pivoting of the suction head from the rest position thereof to the suction position can be biased in order to generate the withdrawing force. 
     
     
       7. A device according to  claim 6 , characterized in that the piston-cylinder arrangement is operatively connected with the second lever mechanism so that by way of the pivot movement of the second lever mechanism the piston-cylinder arrangement is also actuable in order to generate the sub-atmospheric pressure. 
     
     
       8. A device for deblocking optical workpieces, particularly spectacle lenses, comprising:
 a first movement device for rotating a workpiece, which is blocked on a block piece, about a workpiece axis of rotation, 
 a nozzle for delivery of a high-pressure jet of a pressure medium in a direction substantially transverse to the workpiece axis of rotation onto a point of incidence in an edge region between the block piece and the workpiece, and 
 a second movement device for generating a relative movement between the nozzle and the workpiece, 
 the second movement device having a nozzle guide section on which the nozzle is mounted and by which the nozzle is positionable with respect to the block piece under cam control in order to direct the high-pressure jet of pressure medium in defined manner onto the point of incidence, 
 wherein the nozzle guide section comprises a scanning arm which can be brought into operative engagement with an outer circumferential surface of the block piece in order to maintain a substantially constant clear spacing during deblocking between an outlet opening of the nozzle and the point of incidence of the high-pressure jet of the pressure medium in the edge region between the block piece and the workpiece independently of the circumferential profile of the outer circumferential surface of the block piece and the rotational angle position of the block piece about the workpiece axis of rotation, and 
 wherein the scanning arm can be brought by way of a scanning roller rotatably mounted thereon into operative engagement with the outer circumferential surface of the block piece. 
 
     
     
       9. A device according to  claim 8 , characterized in that the nozzle guide section comprises a control plate which co-operates with at least one control cam so as to set an angle of incidence at which the high-pressure jet of pressure medium is incident on the point of incidence in the edge region between block piece and workpiece during the deblocking. 
     
     
       10. A device according to  claim 9 , characterized in that the second movement device comprises a first lever mechanism, to which the nozzle guide section is pivotably coupled and by which the nozzle guide section is movable from a rest position to a working position and vice versa. 
     
     
       11. A device according to  claim 10 , characterized in that the first movement device comprises a spindle which at one end thereof carries the collet chuck for the block piece and at the other end thereof is operatively connected with a handwheel by way of which the spindle and thus the collet chuck are manually rotatable for the deblocking. 
     
     
       12. A device according to  claim 11 , characterized in that the workpiece has a first optically effective surface and a second optically effective surface and prior to the deblocking is blocked by the first optically effective surface on the blocking surface of the block piece, wherein a withdrawal device with a suction head is provided, which for the deblocking can be acted on by a sub-atmospheric pressure in order to firmly suck against the second optically effective surface so that a withdrawing force can be applied to the workpiece by the withdrawing device via the suction head. 
     
     
       13. A system including a device for deblocking an optical workpiece, particularly a spectacle lens, comprising:
 a block piece and workpiece assembly, 
 a first movement device, for rotating the block piece and workpiece assembly, about an axis of rotation of said workpiece, wherein the workpiece is blocked on a defined curved blocking surface of the block piece, 
 a nozzle with an opening for delivery of a high-pressure jet of a pressure medium in a direction substantially transverse to the workpiece axis of rotation onto a point of incidence in an edge region between the block piece and the workpiece, and 
 a second movement device for generating a relative movement between the nozzle and the workpiece, wherein the second movement device has a nozzle guide section on which the nozzle is mounted and by which the nozzle is positionable with respect to the block piece under cam control depending on the curvature of the blocking surface of the block piece in order to direct the high-pressure jet of pressure medium in defined manner onto the point of incidence constructed such that during deblocking the high-pressure jet of pressure medium is set to be incident on the point of incidence at a predetermined incidence angle, 
 the nozzle guide section comprising a control plate which co-operates with at least one control cam so as to set the incidence angle at which the high-pressure jet of pressure medium is incident on the point of incidence in the edge region between block piece and workpiece during the deblocking, 
 wherein the block piece has a clamping section for reception in a collet chuck of the first movement device, wherein the defined curved blocking surface faces away from the clamping section, for fastening of the workpiece, and wherein the at least one control cam has a control surface curved in accordance with the curvature of the blocking surface of the block piece. 
 
     
     
       14. A system according to  claim 13 , characterized in that the blocking surface of the block piece is of spherical construction, whereas the control surface of the at least one control cam is arcuately curved, wherein the at least one control cam is so positionable with respect to the collet chuck that the spherical blocking surface of the block piece received in the collet chuck and the arcuately curved control surface of the at least one control cam are arranged concentrically with respect to a notional center point on the workpiece axis of rotation. 
     
     
       15. A system according to  claim 13 , characterized by a plurality of control cams, which are mounted on a common cam holder, with differently curved control surfaces, wherein the cam holder is constructed to be positionable with respect to the control plate of the nozzle guide section so that depending on the curvature of the blocking surface of the respectively clamped block piece a matching control cam is positionable opposite the control plate. 
     
     
       16. A device for deblocking optical workpieces, particularly spectacle lenses, comprising:
 a first movement device for rotating a workpiece, which is blocked on a block piece, about a workpiece axis of rotation, 
 a nozzle for delivery of a high-pressure jet of a pressure medium in a direction substantially transverse to the workpiece axis of rotation onto a point of incidence in an edge region between the block piece and the workpiece, and 
 a second movement device for generating a relative movement between the nozzle and the workpiece, 
 the second movement device having a nozzle guide section on which the nozzle is mounted and by which the nozzle is positionable with respect to the block piece under cam control in order to direct the high-pressure jet of pressure medium in defined manner onto the point of incidence, 
 wherein the nozzle guide section comprises a control plate which co-operates with at least one control cam so as to set an angle of incidence at which the high-pressure jet of pressure medium is incident on the point of incidence in the edge region between block piece and workpiece during the deblocking, and 
 wherein the control plate can be brought by way of two guide rollers, which are rotatably mounted thereon and the axes of rotation of which are spaced from one another, into operative connection with the at least one control cam. 
 
     
     
       17. A device for deblocking optical workpieces, particularly spectacle lenses, comprising:
 a first movement device for rotating a workpiece, which is blocked on a block piece, about a workpiece axis of rotation, 
 a nozzle for delivery of a high-pressure jet of a pressure medium in a direction substantially transverse to the workpiece axis of rotation onto a point of incidence in an edge region between the block piece and the workpiece, and 
 a second movement device for generating a relative movement between the nozzle and the workpiece, 
 the second movement device having a nozzle guide section on which the nozzle is mounted and by which the nozzle is positionable with respect to the block piece under cam control in order to direct the high-pressure jet of pressure medium in defined manner onto the point of incidence, 
 wherein the nozzle guide section comprises a control plate which co-operates with at least one control cam so as to set an angle of incidence at which the high-pressure jet of pressure medium is incident on the point of incidence in the edge region between block piece and workpiece during the deblocking; 
 wherein the nozzle guide section comprises a nozzle holder on which the nozzle is mounted, and wherein the nozzle holder is connected with the control plate to be angularly adjustable. 
 
     
     
       18. A device for deblocking optical workpieces, particularly spectacle lenses, comprising:
 a first movement device for rotating a workpiece, which is blocked on a block piece, about a workpiece axis of rotation, 
 a nozzle for delivery of a high-pressure jet of a pressure medium in a direction substantially transverse to the workpiece axis of rotation onto a point of incidence in an edge region between the block piece and the workpiece, and 
 a second movement device for generating a relative movement between the nozzle and the workpiece, 
 the second movement device having a nozzle guide section on which the nozzle is mounted and by which the nozzle is positionable with respect to the block piece under cam control in order to direct the high-pressure jet of pressure medium in defined manner onto the point of incidence, 
 wherein the second movement device comprises a first lever mechanism, to which the nozzle guide section is pivotably coupled and by which the nozzle guide section is movable from a rest position to a working position and vice versa. 
 
     
     
       19. A device according to  claim 18 , characterized by a protective hood which is selectively movable from a closed position, in which it closes a working space of the device, to an open position, in which it allows access to the working space, and vice versa, wherein the first lever mechanism is so constrainedly coupled with the protective hood that in the closed position of the protective hood the nozzle guide section is disposed in its working position, whereas in the open position of the protective hood the nozzle guide section is disposed in its rest position. 
     
     
       20. A device according to  claim 19 , characterized in that the first lever mechanism is constrainedly coupled with the protective hood via a cable pull. 
     
     
       21. A device according to  claim 19 , characterized by an electrically driven high-pressure pump which is disposed in fluid connection with the nozzle and which is selectively activatable by way of a switch arrangement, wherein the switch arrangement is actuable by slight manual lowering of the protective hood out of the closed position thereof against a spring force. 
     
     
       22. A device for deblocking optical workpieces, particularly spectacle lenses, comprising:
 a first movement device for rotating a workpiece, which is blocked on a block piece, about a workpiece axis of rotation, 
 a nozzle for delivery of a high-pressure jet of a pressure medium in a direction substantially transverse to the workpiece axis of rotation onto a point of incidence in an edge region between the block piece and the workpiece, and 
 a second movement device for generating a relative movement between the nozzle and the workpiece, 
 the second movement device having a nozzle guide section on which the nozzle is mounted and by which the nozzle is positionable with respect to the block piece under cam control in order to direct the high-pressure jet of pressure medium in defined manner onto the point of incidence, 
 wherein the first movement device comprises a spindle which at one end thereof carries the collet chuck for the block piece and at the other end thereof is operatively connected with a handwheel by way of which the spindle and thus the collet chuck are manually rotatable for the deblocking.